Spun V-grooved sheet metal pulley with thick hub wall integral with thin side wall

ABSTRACT

A method of making a dynamically balanced V-grooved sheet metal pulley from a flat sheet metal disc by roller spinning and splitting tools. The disc is provided with a central hole for mounting the disc on rotating die means between first headstock and tailstock die form assemblies of a spinning machine. The spinning tool presses the disc against an end of a headstock die form and moves generally radially outwardly pressing a portion of the die against the end of the die to provide a circular hub wall. The spinning tool then moves in a series of passes along the headstock die form thereby rolling, forming and ironing the rotating outer metal portions of the disc against the die and forming an axially extending cylindrical side wall terminating in a radially outwardly extending annular flange of a cup-shaped stage blank. The flange then is trimmed to a predetermined length and to form a peripheral axially extending edge on the flange. The cup-shaped blank then is transferred to and clamped between second headstock and tailstock die form assemblies. The clamped cup-shaped blank is rotated and splitting roll means splits the peripheral edge of the annular flange by exerting radial pressure thereon to form a rough V-shaped groove in the flange. Finishing roll means then move radially into the rough V-shaped groove and forms a finished V-shaped pulley groove. Alternately, the spinning tool may thin the metal in the cylindrical side wall during the forming of the cup-shaped stage blank, whereby the finished pulley has a thicker reinforced circular end wall for receiving a hub than the thinned cylindrical side wall.

RELATED APPLICATION

This application is a division of my copending application Ser. No.593,653, filed July 7, 1975 now U.S. Pat. No. 3,995,474, issued Dec. 7,1976.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a method of forming V-grooved sheet metalpulleys from flat sheet metal discs. More particularly, the inventionrelates to a method of roller spinning and splitting a dynamicallybalanced V-grooved pulley in which an annular radially extending flangeis roller spun in a cup-shaped stage blank formed from the disc andsubstantially split to form the pulley V-groove. Furthermore, theproduced pulley may be provided with a reinforced hub flange wallwithout attaching additional reinforcing means thereto, as heretoforerequired.

2. Description of the Prior Art

Many procedures have been used and are known for the formation ofV-grooved sheet metal pulleys from flat sheet metal discs. Many of theseprocedures involve stamping and drawing operations to produce at leastthe cup-shaped blanks from which the V-grooved pulleys are subsequentlyroller spun. Examples of such stamping and drawing operations are shownin U.S. Pat. Nos. 2,493,053 and 3,080,644.

Finished V-grooved pulleys or the cup-shaped stage blanks for subsequentspinning into V-grooved pulleys which are produced by such priorstamping and drawing methods, are not balanced dynamically since thepulleys and blanks are formed by a series of progressive die steps on anon-rotating blank.

Other procedures and apparatus have been known for directly spinning cupblanks and V-grooved pulleys from flat metal discs for producingdynamically balanced pulleys, as shown in U.S. Pat. Nos. 1,680,061 and1,728,002. The equipment and dies required, however, involves headstockdies with sliding and movable members which considerably increase thecost of pulley maufacture with such apparatus. Likewise, these diesrequire means on the machine for controlling movement of the diecomponents which contribute to the increased costs and involvemaintenance problems. Also, considerable tooling costs are involved toprovide various dies from which to produce a variety of cup blanks,since a different die size and configuration is required for each typeof cup blank produced.

Such prior art equipment and processes appear to be satisfactory fortheir intended use especially where vast quantities of cup-shaped blanksand finished spun products are made at high production rates. Such vastquantities spread the cost of the equipment, die and tooling which isexpensive, over the large number of units produced. It is desirable incertain situations and locations to be able to produce a relativelysmall quantity of spun V-grooved pulleys directly from flat sheet metaldiscs with inexpensive, low volume producing equipment and methods.Furthermore, it is desirable to be able to change the size andconfiguration of the V-grooved pulley produced with a minimum toolingcost, so that small quantities of various sizes and configurations ofpulleys can be produced by relatively low initial and replacement costsfor equipment, tooling and dies.

One type of V-grooved pulley commonly produced by various stamping,drawing and spinning procedures and combinations thereof, has a flatbottom wall or hub flange portion which is connected with a generallycylindrical side wall, which in turn terminates in a pair of outwardlyextending annular flanges to form the pulley V-groove. Heretofore,pulley constructions having such elongated cylindrical hub portions havebeen produced by roller spinning the V-groove in the generallycylindrical side wall, which has been formed by stamping and drawingprocedures, as shown in U.S. Pat. No. 2,567,334.

Many applications using such elongated hubbed pulleys require areinforced circular bottom wall for mounting a hub on the pulley, wherethe pulley will experience high torques and forces on the hub area.Prior pulley hub flange walls are reinforced by welding an outerconcentric cup-shaped blank on the hub flange wall area of the pulley toincrease the thickness of the hub flange wall without increasing thethickness of the cylindrical side wall where such reinforcement is notrequired. Other constructions such as shown in U.S. Pat. No. 2,729,110telescopically secure a second cup-shaped blank within the main outercup-shaped shell or blank to achieve the desired thickness. Variousother known pulley constructions use an enlarged hub which forms theentire bottom wall of the pulley and is joined directly to thecylindrical side wall, as shown in U.S. Pat. No. 1,680,061.

Most of these prior pulley constructions having a reinforced hub arearequire additional components or procedures, such as welding, whichincreases the cost of the pulley.

Splitting of the disc-shaped blanks and of cup-shaped blanks is anotherprocedure well known in the art of pulley manufacture to produce aV-grooved pulley, as shown in U.S. Pat. Nos. 1,555,771, 3,087,531 and3,225,425. Pulleys produced by such known methods and procedures have nogenerally cylindrical side wall extending between the hub flange walland the V-groove flanges when produced directly from a flat disc withoutpreviously working the same as shown in U.S. Pat. Nos. 1,555,771 and3,225,425. Also, those pulley blanks having cylindrical side wallportions which terminate in outer annular flanges which are split toform a V-groove have been formed by stamping and drawing procedure, andhave a cylindrical side wall thickness equal to the thickness of the hubflange wall. Such pulleys thus, may not be dynamically balanced andrequire additional manufacturing procedures and components to reinforcethe hub flange wall, where the hub flange wall requires a greaterthickness than the thickness of the cylindrical side wall.

No known method of which I am aware enables the production of relativelysmall quantities of various sizes and configurations of V-groovedpulleys by roller spinning and splitting flat sheet metal discs on usualand simple types of metal spinning machines; which V-grooved pulleys aredynamically balanced due to their complete formations by roller spinningand splitting; and in which the hub flange wall is connected to theV-groove by a generally cylindrical side wall which may be formedthinner than the hub flange wall permitting a pulley to be producedhaving a thick reinforced hub flange wall and thinner side wall withoutrequiring additional components and manufacturing procedures and excessmetal.

SUMMARY OF THE INVENTION

Objectives of the invention include providing new methods and proceduresfor the manufacture from a simple, single sheet metal blank, adynamically balanced V-grooved sheet metal pulley having a flat bottomhub flange wall and a generally cylindrical side wall connecting the hubflange wall with the pulley V-groove; providing such a procedure whichenables small quantities of such V-grooved pulleys to be produced onrelatively inexpensive and simple lathe type metal spinning andsplitting machines with a minimum of tooling costs, requiring basicallya pair of headstock die forms having an outer configurationcomplementary to the internal shape of the pulley cylindrical side walland hub flange wall, a pressure forming roller for laying the metal of aflat disc blank against the headstock die form during a series of passesof the roller with respect to the die form, and a splitting roller forseparating a peripheral edge of an annular flange formed from the discblank into a pair of converging flanges forming the V-groove of thepulley; providing such a procedure which requires only replacing theheadstock die form of a spinning machine to make pulleys having varioussizes and configurations of cylindrical side walls and flat hub flangewalls, and which enables rapid and inexpensive changeover to producesuch different pulleys; providing such a procedure which preferably maybe automatically program controlled enabling an unskilld workman tooperate a plurality of such metal spinning and splitting machines forcarrying out the steps of the improved method; providing such aprocedure which enables a V-grooved pulley to be formed having a thickreinforced hub flange wall with a thinner cylindrical side wall reducingthe amount of metal required for formation of the pulley and eliminatingadditional components and procedures heretofore required to reinforcethe hub flange wall; and providing a new procedure and method for makingsuch dynamically balanced V-grooved pulleys having the pulley V-grooveformed in an annular flange at the open end of a cylindrical side wallby splitting, which side wall and flange is formed by roller spinningfrom a disc shaped metal blank, which eliminates difficulties heretoforeencountered, achieves the various objectives indicated in a practical,workable and easily controlled manner, and which solves problems andsatisfies needs which have long existed in the art.

These objectives and advantages are obtained by the improved V-groovedpulley manufacture which produces a sheet metal pulley of the typehaving a bottom hub flange wall and a connected outer generallycylindrical side wall terminating in a pair of annular flanges extendingoutwardly of the cylindrical side wall and forming a V-groovetherebetween, from a flat sheet metal disc including the steps of,providing a flat sheet metal disc having a central hole formed therein;clamping a central portion of the disc around the hole between opposedrelatively axially movable complementary clamping faces of rotatablefirst headstock and tailstock die means wherein the first headstock diemeans also has cylindrical flange-forming means terminating in radiallyoutwardly extending annular flange-forming means; rotating the first diemeans and clamped disc; pressure rolling, forming and ironing therotating annular disc metal portions surrounding the central portionagainst the first headstock die means cylindrical and annularflange-forming means to form a cup-shaped stage blank with a flat bottomhub flange wall and a connected axially extending generally cylindricalside wall terminating in a radially outwardly extending annular flangehaving an extended end portion; trimming the extended end portion of theannular flange to a predetermined radial length with respect to thecylindrical side wall thereby forming an axially extending flatcircumferential edge on the annular flange; removing the formedcup-shaped stage blank from the first die means; clamping the hub flangewall and connected cylindrical side wall of the cup-shaped stage blankbetween clamping surfaces of second headstock and tailstock die means,wherein said second headstock and tailstock die means includes conicalsurfaces forming a generally annular V-shaped die groove, and locatingthe annular stage blank flange within said die groove; rotating thesecond die means and clamped cup-shaped blank; splitting said annularflange to rough form a pair of annular angularly extending V-grooveflanges of a V-shaped pulley groove by applying radial pressure to theflat circumferential edge of said annular flange with splitting rollmeans; and then roller forming a finished V-shaped pulley groove bypressure forming and ironing the rough formed V-groove flanges againstits second die means conical surfaces.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred method steps of the invention - illustrative of the best modein which applicant has contemplated applying the principles - are shownin the drawings and set forth in the following description, and areparticularly and distinctly pointed out and set forth in the appendedclaims.

FIG. 1 is a fragmentary diagrammatic top plan view of portions of a typeof simple spinning machine which may be used to carry out steps of thenew procedure;

FIG. 2 is a somewhat diagrammatic fragmentary sectional view of a flatsheet metal blank disc mounted between headstock and tailstock dies ofthe spinning machine shown in FIG. 1, and showing the spinning of theflat bottom hub flange wall of the V-grooved pulley being produced bythe improved procedures;

FIG. 3 is a view similar to FIG. 2 showing a step of the improved rollerspinning operation in which an intermediate annular portion of the blankdisc is being layed along the headstock die form preparatory to formingan outwardly radially extending flange;

FIG. 4 is a view similar to FIGS. 2 and 3 showing the steps ofcompleting the roller forming of the cylindrical hub side wall andannular flange in the disc blank;

FIG. 5 is a view similar to FIGS. 2-4 showing a trimming operation beingperformed on the outer edge portion of the annular flange, completingformation of a cup-shaped stage blank;

FIG. 6 is a fragmentary diagrammatic top plan view of portions of asimple lathe-type machine which may be used to carry out the splittingand V-groove forming steps of the new procedure;

FIG. 7 is a somewhat diagrammatic fragmentary sectional view of thecup-shaped stage blank produced by the steps of FIGS. 1-5, mountedbetween headstock and tailstock dies of the machine shown in FIG. 6, andshowing a splitting roll at an initial engagement position with acircumferential edge of the annular flange;

FIG. 8 is a view similar to FIG. 7 showing the splitting roll uponcompletion of the splitting operation performed on the annular flangeproducing a rough V-groove therein;

FIG. 9 is a somewhat similar view to FIGS. 7 and 8 showing a finishingroll completing the formation of the finished V-groove from the roughV-groove produced by the splitting roll of FIGS. 7 and 8;

FIG. 10 is a side elevational view of a completed spun V-grooved pulleyformed from the flat metal disc by the roll spinning and splitting stepsshown in FIGS. 2-9;

FIG. 11 is a sectional view of a type of prior art cup-shaped blankhaving a hub flange wall reinforcing cup blank attached thereto;

FIG. 12 is a somewhat diagrammatic fragmentary sectional view similar toFIGS. 2 and 3 showing a flat sheet metal disc mounted between headstockand tailstock dies of a spinning machine, with the headstock die formingthe flat bottom hub flange wall and the remaining portion of the discblank being formed about the headstock die cylindrical side wall incarrying out the steps of the improved method to form a modifiedV-groove pulley having a reinforced hub flange wall;

FIG. 13 is a view similar to FIG. 12 showing the initial steps of rollerforming, ironing and thinning an intermediate steps of roller forming,ironing and thinning an intermediate annular portion of the metal discto form a thinned cylindrical side wall integrally connected to athickened hub flange wall;

FIG. 14 is a view similar to FIGS. 12 and 13 showing completion of thesteps of forming the thinned cylindrical side wall and annular flange ofa cup-shaped stage blank; and

FIG. 15 is a fragmentary diagrammatic sectional view of the headstockand tailstock dies of a splitting machine similar to the machine of FIG.6 upon completion of the splitting operation by a splitting roll andjust prior to complete formation of the finished pulley V-groove by afinishing roll for the pulley construction shown in FIGS. 12-14;

FIG. 16 is a fragmentary diagrammatic sectional view similar to FIG. 14showing the steps of roller forming, ironing and thinning anintermediate portion of a metal disc to form a tapered thinnedcylindrical side wall integrally connected to a thicker hub flangebottom wall;

FIG. 17 is a fragmentary diagrammatic sectional view similar to FIG. 15of a headstock and tailstock die of a splitting machine upon completionof the splitting operation by a splitting roll, just prior to completeformation of the finished pulley V-groove by a finishing roll for thepulley blank shown in FIG. 16;

FIG. 18 is a diagrammatic fragmentary sectional view of a flat sheetmetal blank disc clamped between a modified headstock die form and atailstock die, showing the start of forming a modified cup-shaped pulleyblank;

FIG. 19 is a view similar to FIG. 18 showing the steps of thinning andforming a cylindrical annular flange in the disc blank;

FIG. 20 is a view similar to FIGS. 18 and 19 showing another step of theimproved roller spinning method showing the thinning and forming of areentrant flange connecting the annular cylindrical flange with areinforced hub bottom wall of the modified cup-shaped blank;

FIG. 21 is a view similar to FIGS. 18-20 showing a trimming operationbeing performed on the open end portion of the annular flange of thecompleted modified cup-shaped pulley blank; and

FIG. 22 is a generally diagrammatic fragmentary view showing theformation of a pulley V-groove in the annular cylindrical flange wall ofthe modified cup-shaped metal blank having a reinforced bottom hub walland thinned cylindrical side wall construction;

Similar numerals refer to similar parts throughout the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A portion of a typical simple lathe type spinning machine for carryingout certain of the steps of the improved roller forming and splittingmethod is shown in FIG. 1, and is indicated generally at 1. Spinner 1includes a bed 2, a headstock assembly 3 and a tailstock assembly 4. Aheadstock die form 5 is mounted on headstock assembly 3 and is rotatedby a motor driven shaft (not shown).

Tailstock assembly 4 preferably has a die form 7 axially movable bypiston rod 8. An aperture 9 is formed in tailstock die 7 for receiving apilot pin 10 formed on and extending axially outwardly from the centerof headstock die 5 (FIG. 2).

A tool holder 11 is movably mounted on a cross feed carriage 12 which inturn is movably mounted on a pair of guide rods 13 for longitudinalaxial movement between headstock 3 and tailstock 4. A pressure spinningroller 14 is rotatably mounted on tool holder 11 and is movable both inparallel and transverse directions with respect to the longitudinal axisof spinning machine 1 by manipulation along cross feed carriage 12 andguide rods 13.

A metal trimming wheel assembly 15 is mounted on a second cross feedcarriage 16 which in turn is mounted on guide rods 13. Assembly 15includes a trimming wheel 17 for trimming the edge portions of anannular flange formed on a cup-shaped stage blank produced in accordancewith the procedures set forth below.

The particular construction and arrangement of roller spinning machine 1and the components thereof, may be modified and changed withoutaffecting the concepts of the invention. The important features broughtout by the construction of machine 1 shown in FIG. 1, is the relativesimplicity thereof in contrast with the known complex prior art spinningmachines used for a variety of spinning procedures.

The improved roller spinning procedures for producing a cup-shaped metalstage blank having an outturned annular flange for subsequent splittingand formation into a pulley V-groove, is set forth diagrammatically inFIGS. 2-5, with the splitting and V-groove forming procedures beingshown in FIGS. 6-9. A spun metal V-grooved pulley produced by the stepsof FIGS. 2-9 is shown in FIG. 10 and indicated at 6.

A flat sheet metal disc blank 20 is clamped between a circular end face18 of tailstock die 7 and a larger circular flat face 19 of headstockdie form 5 by actuation of a cylinder or the like controlling piston rod8. Pilot pin 10 projects through a central hole 21 formed in disc 20 andinto aperture 9 of tailstock die 7 to properly align and center disc 20on headstock die 5 of spinning machine 1.

The tool or roller 14 is guided into contact with a central portion ofrotating blank disc 20 which is adjacent to and surrounds tailstock die7 as shown in dot-dash lines in FIG. 2 by the concurrent movement ofcross carriage 12 and tool holder 11 until pressure is exerted on disc20. Roller 14 then moves in a transversely, radially outwardly extendingdirection with respect to the longitudinal axis of machine 1 forcing theannular portion of disc 20 surrounding the clamped central portionagainst the outer periphery of flat end face 19 of die 5. Sufficientpressure is exerted by roller 14 on discs 20 during this outward radialmovement to iron out any indentation, gauge variation or otherirregularity of disc 20 without materially reducing the originalthickness of disc 20, and to form the dynamically balanced central flatbottom hub flange wall 24 of a cup-shaped stage blank from which a finalspun V-grooved pulley is produced.

Carriage 12 then moves longitudinally along guide rods 13 forwardlytoward headstock die 5 simultaneously with the radially outward movementof tool holder 11. Roller 14 follows a general diagonal path pressingthe unclamped outer portion of disc 20 to the position shown in dot-dashlines of FIG. 3. Roller 14 by a series of passes along and radially withrespect to headstock die 5, works and forms this outer portion of disc20 which surrounds the flat bottom flange wall 24 forwardly against acylindrical flange forming wall 23 of the headstock die to start theformation of a complementary cylindrical side wall 25 of a pulley hub.

In accordance with the invention, the next series of operations andsteps of the improved process completes the formation of cylindrical hubside wall 25 and forms a radially outwardly extending annular flange 26(FIG. 4). Roller 14 moves generally axially toward headstock die form 5from the dot-dash line position indicated at 27 to the dot-dash lineposition 28. The roller forms and irons the metal of an intermediateportion of the disc along and against cylindrical flange forming sidewall 23 of die 5. This metal working forms the axially extendingcylindrical hub side wall 25 which is integrally connected to the hubflange wall 24 by a generally right angled corner 29. Corner 29 iscomplementary to a corresponding die corner 30 connecting headstock dieface 19 with cylindrical die wall 23.

Roller 14 then forms, irons and presses a portion of the metal of disc20 into a second right angled corner 31 formed in die form 5 whichconnects die cylindrical side wall 23 with a flange forming die wall 32(FIG. 4). This working forms a complementary right angled corner 33 andthe annular flange 26 in disc 20 adjacent cylindrical hub wall 25, withcorner 33 connecting flange 26 with cylindrical hub wall 25 at agenerally right angle. Flange 26 thus extends radially outwardly fromcylindrical side wall 25 adjacent an open end 34 formed by side wall 25.

The next step involves the trimming of the extended somewhat irregularend 35 of annular flange 26 to a predetermined radial length withrespect to cylindrical side wall 25. Trim assembly 15 moves axiallytoward headstock die form 5 on guide rods 13 (FIG. 5) with trimmingwheel 17 forming a flat axially extending edge 36 on the outermost endof flange 26 upon removal of irregular end 35. This trimming operationcompletes the formation of a dynamically balanced cup-shaped stage blankindicated generally at 37, comprising flat circular hub flange wall 24,and cylindrical hub side wall 25 which is joined to flange wall 24 byright-angled corner 29. Cylindrical wall 25 terminates in radiallyoutwardly extending annular flange 26, which in turn is connected by asecond right-angled corner 33 to side wall 25.

The dynamically balanced cup-shaped stage blank 37 then may be removedeither manually or automatically, from die 5 of spinning machine 1 andplaced on a headstock die assembly 38 of a metal splitting machine,indicated generally at 39 (FIG. 6).

Splitting machine 39 has a simple lathe-type construction as doesspinning machine 1, and includes headstock die assembly 38 and atailstock die assembly 40. A headstock die form 41 is mounted onheadstock assembly 38 and is rotated by a motor driven shaft as isheadstock die form 5. A hydraulic or pneumatic operated piston mechanism42 moves tailstock die assembly 40 axially with respect to headstock dieassembly 38.

Headstock die form 41 (FIG. 7) includes a flat end face 43, acylindrical side wall 44 and a conical annular flange 45. End face 43and side wall 44 are similar to end face 19 and side wall 23 of die form5 and are complementary to hub flange wall 24 and side wall 25 of stageblank 37. Tailstock die assembly 40 is formed with a generallycylindrical-shaped die cavity 46 (FIGS. 6-9) having a flat bottom wall47 and a cylindrical side wall 48 complementary with hub flange wall 24and cylindrical side wall 25 of cup-shaped blank 37. Die cavity sidewall 48 terminates in an outturned rearwardly extending conical flange49 which cooperates with conical flange 45 of headstock die 41 to form aV-shaped annular groove 50.

Splitting machine 39 (FIG. 6) has a splitting roll 51 and a V-grooveforming roll 52 mounted on cross feed mechanisms 53 and 54,respectively, for transverse radial movement with respect to thelongitudinal axis of splitting machine 39. Rolls 51 and 52 preferablyare mounted diametrically opposite each other as shown in FIG. 6.

Stage blank 37 is clamped between headstock and tailstock die forms 41and 40 as shown in FIGS. 6 and 7, with annular flange 26 being locatedwithin V-shaped groove 50. Clamped stage blank 37 then is rotated andsplitting roll 51 is moved radially inwardly with its peripheralsplitting edge 55 engaging the midpoint of circumferential edge 36 oftrimmed flange 26. Roll 51, as it moves radially inwardly, splits flange26 into a pair of angularly extending integrally connected V-grooveflanges 56 and 57 (FIG. 8) which form a rough V-groove 58 therebetween.The outer ends of formed V-groove flanges 56 and 57 are flared slightlyoutwardly at 59 and 60, respectively, upon engagement with annularshoulders 61 formed on roll 51 adjacent splitting edge 55.

Forming roll 52 (FIG. 9) moves radially inwardly, generallysimultaneously with the inward movement of splitting roll 51, with rollforming edge 62 entering the formed rough V-groove 58 with forming edge62 just lagging splitting edge 55. Roll 52 forms, presses and ironsflanges 56 and 57 against conical flanges 45 and 49 to provide afinished pulley V-groove 63 in flange 26. Shoulders 64, which are formedon roll 52 adjacent forming edge 62, shapes and forms flared ends 59 and60 of V-groove flanges 56 and 57 upon forming edge 62 reaching itsinnermost position as shown in FIG. 9.

The finished spun V-grooved pulley 6 produced by the steps of theimproved method shown in FIGS. 1-9 is shown in FIG. 10. Pulley 6includes hub flange wall 24, and generally axially extending hub sidewall 25 which terminates in the pair of V-groove flanges 56 and 57forming pulley V-groove 63. Hub flange wall 24 and cylindrical hub sidewall 25 preferably have a metal thickness equal to the thickness of discblank 20 except for minor gauge variations and manufacturing tolerance,with flanges 56 and 57 each having an approximate thickness of one-halfthat of disc 20.

Many applications require a pulley having a generally elongated axiallyextending hub portion, similar to cylindrical side wall 25, with a thickreinforced hub flange wall 24, for attaching or mounting a hub thereon.Usually the cylindrical side wall need not be as thick as such areinforced hub flange wall, thus resulting in excess metal and weightwhen the pulley is formed by known spinning and die stamping and drawingprocedures. Alternately, a cup-shaped end cap 65 (FIG. 11) is welded tothe exterior or interior of a usual cup-shaped blank 66 to reinforce thehub flange wall area 67 without increasing the thickness of cylindricalside wall 68, thereby increasing the pulley cost.

FIGS. 12-15 illustrate the spin forming and splitting of a modifiedV-grooved pulley similar to the pulley 6 of FIG. 10, but having athicker reinforced hub flange wall 69 than a connected cylindrical hubside wall portion 70. A flat sheet metal disc 71, having a generallyuniform metal thickness, as shown in FIG. 12, preferably of greaterthickness than disc 20, is placed on a pilot pin 72 of a headstock dieform 73. The central portion of disc 71 is clamped against a flat endface 74 of die form 73 by tailstock die 7.

Headstock and tailstock dies 73 and 7 are rotated and pressure-formingroller 14 is moved into pressure engagement with the unclamped portionof disc 71 adjacent tailstock die 7. Roller 14 moves generally radiallyoutwardly and then simultaneously axially from the inner dot-dash lineposition 75 (FIG. 12) to the outer dot-dash line position 76 whilepressure rolling, forming and ironing an annular metal portion of disc71 against end face 74 and partially about die corner 77. Roller 14 thenmoves in a series of passes generally axially along a cylindrical sidewall 78 of headstock die form 73 laying an intermediate annular metalportion of the disc generally along the cylindrical side wall portion78, as shown in solid lines, FIG. 12. This metal working forms aright-angled corner 79 in the metallic disc complementary to die corner77, and an annular cylindrically-shaped band or zone 80 adjacent corner79. Annular band 80 preferably has the same metal thickness as hubflange end wall 69 and provides reinforcement for corner 79. Band 80 isformed by roller spinning of the metal into a complementary annularrecess or relief 81 formed in die 73.

In accordance with the invention, roller 14 then moves axially alongheadstock side wall 78 and pressure forms, irons and thins the metal ofthe intermediate annular portion against side wall 78 axially fromannular band 80 to adjacent a flange forming die corner 82, similar tocorner 31 of die 5 (FIG. 14). This thinning procedure forms the axiallyextending cylindrical side wall 70 somewhat similar to side wall 25 ofcup-shaped blank 37. Roller 14 then moves radially outwardly forming andironing an annular end portion of disc 71 against an annular flangeforming surface 83 of die form 73 to form a radially outwardly extendingannular flange 85, similar to flange 26 of stage blank 37.

An end portion 86 of flange 85 then is trimmed by wheel 17 in a similarmanner as shown in FIG. 5, to provide flange 85 with a predeterminedradial length for forming a pulley V-groove therein. The trimmingoperations also provides flange 85 with a flat axially extendingcircumferential edge (not shown) similar to edge 36 of flange 26.

Flange 85 preferably is not thinned when being worked by roller 14 (FIG.14) as is side wall 70, and only is pressed and ironed against flangeforming surface 83 to conform thereto and to remove any gaugevariations, indentations and irregularities in the metal. Side wall 70is thinned to a predetermined thickness, for example, one-half thethickness of disc 71 and of hub flange wall 69. The amount of thinningwill be dependent upon the axial length of cylindrical die side wall 78since as the metal is thinned, it is moved axially along side wall 78toward flange forming surface 83 until the desired thickness isachieved. The remaining annular unworked section of original metalthickness then is laid against and formed along die flange surface 83 toform annular flange 85.

The modified cup-shaped stage blank 87 produced by the steps of FIGS.12-14, then is removed from headstock die form 73 of spinner 1 andplaced on a modified headstock die form 88 mounted on splitting machine39 (FIG. 15) or a similar lathe-type machine. A modified tailstock die89 then clamps stage blank 87 on splitting machine 39. Headstock andtailstock dies 88 and 89 are similar to headstock and tailstock dies 41and 40 except for the greater axial lengths of cylindrical side wallsurfaces 90 and 91 of dies 88 and 89, respectively, which correspond tocylindrical side wall surfaces 44 and 48 of dies 41 and 40. An annularV-groove 92 is formed between conical surfaces 93 and 94 of dies 88 and89 into which flange 85 extends when in clamped position, similar toV-groove 50 of FIG. 7.

Splitting roll 51 and finishing roll 52 then move radially inwardlyforming a pair of V-groove flanges 96 and 97 defining a pulley V-groove98 therebetween (FIG. 15). Flanges 96 and 97 preferably are formed withslightly flared ends 98a by splitting roll 51 which are finished byshoulders 64 on roll 52. Cylindrical side wall 70 of stage blank 87 mayhave the same axial length as side wall 25 of cup-shaped blank 37 merelyby starting with a smaller diameter blank disc and thinning the metalsufficiently until the desired length is achieved.

Blank 87, thus provides a cup-shaped stage blank for subsequentlyforming pulley grooves in the cylindrical side wall which has areinforced hub flange wall 69 of various desired thicknesses, whichthickness preferably is equal to the thickness of the starting blank.One or more V-grooves also may be roller spun directly into the thinnedside wall 70 of cup-shaped blank 87 and into side wall 25 of stage blank37 by procedures described in U.S. Pat. Nos. 2,869,223 and 3,852,863.

Fundamental facets of the new concept involve the procedures for thespinning and subsequent splitting operations for the manufacture of aV-grooved pulley from a dynamically balanced cup-shaped pulley blankhaving an annular radially extending flange which is roller split toform a pulley V-groove; and in which the annular flange is connected toa flat hub flange wall by an axially extending side wall, which in turnmay be thinned during its formation to provide a thicker reinforced hubflange wall eliminating excess wasted metal in the side wall.

A slightly modified form of the invention of FIGS. 12-15 is shown inFIGS. 16 and 17. In general, roller 14 pressure rolls, forms, irons, andthins an intermediate annular metal portion of disc blank 71 to form athinned axially extending, generally cylindrical hub side wall 100similar to side wall 70 of modified cup-shaped blank 87, in which themetal thickness of side wall 100 is tapered downwardly from a hub flangewall 106 towards an annular flange 111. This tapering spinning procedureforms further modified cup-shaped stage blank 99 similar to stage blank87 except for tapered cylindrical hub wall 100 (FIG. 16).

Roller 14 moves generally radially outwardly and then axially fromposition 101 (FIG. 16) to position 102 while pressure rolling, formingand ironing an annular metal portion of disc 71 against end face 103 ofheadstock die form 104 and about die corner 105. This metal workingforms hub flange wall 106 and a generally right-angled corner 107 in themetallic disc complementary to die end face 103 and corner 105, both ofwhich have a metal thickness generally equal to that of starting discblank 71.

Roller 14 continues to move in a series of passes generally axiallyalong a tapered portion 108a and a cylindrical portion 108b of a sidewall 108 of headstock die form 104 from position 102 to position 109(FIG. 16) thinning and tapering the metal of an intermediate annulardisc portion against side wall portions 108a and 108b toward a flangeforming die shoulder 110. This metal working forms the generally axiallyextending side wall 100 consisting of a tapered portion 100a and athinned cylindrical portion 100b. Side wall 100 is generally similar toside walls 25 and 70 of cup-shaped blanks 37 and 87, respectively, buthaving the tapered, thinned metal thickness portion 100a.

This tapering metal thickness in side wall 100 eliminates forming of theannular band 80 adjacent hub flange wall 69 of stage blank 87 to providereinforcement for corner 79. This taper configuration providesadditional metal in the areas of side wall 100 adjacent hub flange wall106 without the excess metal in the side wall area adjacent the annularflange means from which a pair of V-groove flanges are to be formed. Theouter diameter of side wall 100 preferably remains constant throughoutthe length thereof with the taper being provided in the side wall withrespect to the inner diameter as shown in FIG. 16. If desired, the tapercan be provided with respect to the outer diameter, with the innerdiameter of side wall 100 remaining constant (not shown), or acombination thereof without departing from the concept of the invention.

Roller 14 then forms a radially outwardly extending flange 111 similarto flanges 26 and 85 at the thinned end of tapered side wall 100. Flange111 preferably has a metal thickness equal to the thickness of theoriginal disc blank and of hub flange wall 106.

FIG. 17 is similar to FIG. 15 and shows the steps of roller workingannular flange 111 to form a pair of V-groove flanges 112 and 113therein similar to V-groove flanges 96 and 97 of pulley V-groove 92, andthus need not be described in detail.

A still further modification of the invention is shown in FIGS. 18-22wherein a spun metal V-grooved pulley 115 (FIG. 22) is produced from aspun metal cup-shaped stage blank 116 (FIG. 21). Stage blank 116 has areinforced hub flange bottom wall 117, a generally cylindrical hubflange side wall 118, a reentrant conical flange 119, and a cylindricalannular flange wall 120. Conical flange 119 is roller formed in flatsheet metal disc blank 71 in a similar manner as described in mycopending application, Ser. No. 584,388, filed June 6, 1975 now U.S.Pat. No. 3,991,598, issued Nov. 16, 1976.

Sheet metal disc blank 71 is clamped between die end face 121 oftailstock die 122 and a flat complementary end face 123 of headstock dieform 124 (FIG. 18). Roller 14 preferably pressure forms, rolls and ironsan annular portion of disc 71 surrounding the central clamped areaagainst end face 123, forming hub flange bottom wall 117. This metalworking maintains the general metal thickness of disc 71 upon formingbottom wall 117 to provide a reinforced thick hub flange wall for thespun V-grooved pulley 115. Sufficient pressure is exerted by roller 14during this initial outward radial movement to iron out any indentationgauge variation or other irregularity of disc 71 without materiallyreducing the original metal thickness.

Roller 14 moves in a series of diagonally extending passes between thedot-dash line positions 125 and the full-line position 126 (FIG. 18)partially forming a corner 127 and laying an intermediate annular metalportion of disc 71 surrounding hub flange wall 117 generally alongheadstock die 124. Roller 14 then moves axially between dot-dash lineposition 128 and full-line position 129 (FIG. 19) forming, ironing,thinning and elongating the outer annular portion of the disc along andagainst a cylindrical side wall 130 of die 124. This metal working formsaxially extending cylindrical annular flange wall 120 integrallyconnected to an intermediate annular metal disc portion 150 extendingbetween hub flange bottom wall 117 and flange wall 120.

Roller 14 then forms, irons, thins and presses intermediate portion 150of the metal disc into an acutely-angled corner 131 formed in die form124 (FIG. 20) which connects a die hub side wall 136 with a reentrantconical flange forming die wall 132. This working forms a complementaryacutely angled corner 133 (FIG. 21) between conical reentrant flange 119and hub side wall 118 in disc 71, with corner 133 connecting hub wall118 and reentrant flange 119 at an approximately 72° included angle.

In accordance with the invention, die hub side wall 136 is tapered,whereby the roller working of intermediate metal blank portion 150 thinsand tapers the metal thickness of hub side wall 118 providing sufficientmetal thickness adjacent corner 127 and hub bottom wall 117 forreinforcement, yet reducing the metal thickness adjacent conical flange119.

The next step involves the trimming of the extended somewhat irregularend 140 of annular flange 120 which forms the cup end opening 141 to apredetermined axial length with respect to hub wall 118 by a trimmingwheel 142. Trimming wheel 142 may be of the type described in U.S. Pat.No. 2,702,597.

The dynamically balanced cup-shaped blank 116 which is roller spun inaccordance with the above described steps of the improved method,comprises the flat circular bottom hub wall 117 having a metal thicknessgenerally equal to the thickness of the original disc blank 71. Inaccordance with the invention, hub side wall portion 118, reentrantflange 119 and annular flange wall 120 are elongated and thinned duringthe metal working thereof to provide cup-shaped blank 116 with areinforced bottom hub wall 117 and thinned cylindrical side wall flange120 connected thereto for forming a pair of pulley V-groove flanges.Likewise, hub side wall 118 may be tapered as shown in FIG. 21.

Cup-shaped blank 116 then is removed either manually or automaticallyfrom die 124 and placed on a pulley forming headstock die 143, a portionof which is shown in FIG. 22, which preferably is mounted on a second ordifferent spinning machine.

A V-groove forming roll 144, or a plurality of rough and finishingpulley groove forming rolls of the type shown in U.S. Pat. No. 2,826,804is moved transversely radially inwardly engaging the midpoint of thinnedcylindrical flange wall 120 of pulley blank 116 (FIG. 22). Roll 144 incombination with the axial movement of a tailstock die assembly 145forms a V-groove 146 in the annular flange wall. Reentrant flange 119forms a double thickness flange wall 147 of V-groove 146 together with amatching second flange wall 148 formed from a portion of the metal ofthinned flange wall 120. An opposite V-groove flange wall 149 alsoformed from flange wall 120 completes the forming of V-groove 146.

Spinning machine 1 and splitting machine 39 preferably will becontrolled and programmed by pneumatic, hydraulic and electroniccomponents and devices well known in the spinning machine art. Anoperator need only actuate a cycle start button causing tool holder 11and trimming assembly 15 to advance through a programmed series ofoperations to completely spin form cup-shaped stage blanks 37, 87, 99and 116. The spun stage blanks 37 and 87 then are removed and placed onsplitting machine 39 which in turn may be automatically controlled andprogrammed to perform the splitting and finished V-groove formingprocedures. Likewise, headstock die 5 need only be replaced by headstockdies 73, 104 and 124 with a subsequent reprogramming of the machinecontrol cycle to change from production of pulley stage blanks 37 tostage blanks 87, 99 and 116.

Accordingly, the present invention provides substantial improvements inthe art of making roller spun V-grooved pulleys of the type having a hubflange wall and an elongated axially extending side wall hub portionintegrally connected thereto, which terminates in a pair of angledradially extending flanges forming a pulley V-groove therebetween;provides for the manufacture of such a statically and dynamicallybalanced concentric sheet metal V-grooved pulley in which the hub flangewall may have various thicknesses to provide the desired strength tomeet various design criteria, which thickness preferably is equal to thethickness of the sheet metal blank disc from which it is formed, and inwhich the axially extending side wall may have a thickness less thanthat of the metal of the original blank disc to reduce the weight andmaterial cost for such pulleys; and provides a method which satisfiesthe various objectives set forth, which solves problems and satisfiesdemands existing in the art, and which obtains the new resultsindicated.

In the foregoing description, certain terms have been used for brevity,clearness and understanding; but no unnecessary limitations are to beimplied therefrom beyond the requirements of the prior art, because suchterms are used for descriptive purposes and are intended to be broadlyconstrued.

Moreover, the description and illustration of the invention is by way ofexample, and the scope of the invention is not limited to the exactdetails shown or described or to the exact pulley blank shape, dies,rolls and pulleys shown, since they may be varied to provide otherstructural embodiments.

Having now described the features, discoveries and principles of theinvention, the manner in which the new roller spun V-grooved sheet metalpulleys may be manufactured, the details of the steps of improvedmethod, and the advantageous, new and useful results obtained; the newand useful inventions, constructions, devices, parts, elements,arrangements, combinations, sub-combinations, methods, steps,procedures, operations, discoveries, principles and products are setforth in the appended claims.

I claim:
 1. Spun V-grooved sheet metal pulley construction of the type having a cup shape provided with a flat circular hub wall of generally uniform metal thickness with a central opening formed in the hub wall for mounting a hub on the pulley, and a generally axially extending side wall integrally connected to the outer periphery of the hub wall and terminating in an integral pair of annular angularly extending V-groove flange walls forming a V-shaped pulley groove; the improvement in which the generally axially extending side wall has a metal thickness less than the metal thickness of the integrally connected hub wall to provide the pulley with a reinforced hub wall integral with the thinner side wall.
 2. The pulley construction set forth in claim 1 in which the metal thickness of a portion of the side wall adjacent the hub wall is uniformly tapered toward the V-groove flanges, whereby said side wall has a greater metal thickness adjacent the hub wall than adjacent the V-groove flanges.
 3. The pulley construction set forth in claim 1 in which the metal thickness of the side wall is generally uniform through the length of said side wall and is approximately one-half the metal thickness of the hub wall.
 4. A spun V-grooved pulley construction of the type having a one-piece sheet metal cup shape with a hub wall and an annular side wall terminating in an open end; the annular side wall having a metal thickness less than the metal thickness of the hub wall; annular V-groove-forming walls integrally connected to the side wall at its open end; and the thickness of the hub wall being greater than the thickness of at least one of the V-groove-forming walls.
 5. The pulley defined in claim 4 in which the thickness of the hub wall is greater than the total thickness of both V-groove-forming walls.
 6. The pulley defined in claim 4 in which the thickness of the hub wall is equal to the total thickness of both V-groove-forming walls. 